"Is there such a thing as wanting too much sex? He says I don't want it enough. I think he wants it too much. He fully admitted to thinking twice a day would be good. I think that's excessive considering that we are parents and have lives. Is there some study out there about this issue?"

It sounds like you and your partner may have a sexual desire discrepancy, a situation in which two people prefer different amounts or types of sex. Believe it or not, this is one of the most common sexual problems out there. Consider this: a national survey of British adults found that 27.4% of women and 23.4% of men reported having a sexual desire discrepancy.

In case you aren't familiar with the term "lifehack," it refers to any "tool or technique that makes some aspect of one's life easier or more efficient." Based on the frequent requests for advice I receive from readers of Sex and Psychology, our relationships are one of those areas in which there seems to be great demand for a few solid lifehacks. To that end, I've compiled a video playlist below of five of the most useful ones I've come across to date. Check it out, and hack away!

People and governments across the globe have been working to legalize same-sex marriage for the last 15 years. At first, the rate of legalization was best described as a slow trickle; however, the movement has picked up steam recently. The infographic below offers a look at where things currently stand and highlights some of the important milestones along the way.

This is a really interesting question, so thanks for asking it! I’m going to assume that by “sexual orientation” you’re referring to one’s sexual identity label. Of course, this is not how everyone defines sexual orientation (e.g., some think of it as a pattern of attraction or arousal, others as a pattern of behavior); however, I have found that in everyday (i.e., non-academic) usage, most people are referring to the label we use to describe ourselves, so that’s what I’ll focus on here.

Although casual sex is something that most Americans have done before, it is a sexual activity that continues to be viewed in a largely negative light. For instance, casual sex is frequently portrayed in the popular media as risky and as a "lesser" form of sex. But is this negative reputation deserved? In this TEDx talk, Dr. Zhana Vrangalova explores what the science on casual sex has revealed, including its potential benefits and risks, men's and women's most common psychological reactions to it, and how experiences with casual sex are linked to our long-term relationship outcomes. Dr. Vrangalova's nuanced analysis reveals that casual sex can affect different people in very different ways, which means that casual sex isn't inherently a good or bad thing. Indeed, who you are, how you're doing it, and why you're doing it are critical to understanding the effects of casual sex. Check out the video below to learn more.

Male circumcision, or the removal of the penile foreskin, is a procedure performed on most male infants in the United States today. Although the rate of circumcision has declined during the last few decades, it continues to be widely performed in the U.S. for many reasons. However, circumcision has grown increasingly controversial. In addition, it is not uncommon to hear circumcised men lament the removal of their foreskin and express a desire to be "uncircumcised." In light of this, some have wondered whether there is anything that can be done in cases like this. That is, is it possible to restore foreskin post-circumcision?

In a new study published in Evolutionary Psychological Science, researchers examined whether the timing, quantity, and quality of men's ejaculate changes when they masturbate to images of a familiar woman compared to a woman they have never seen before. The results (and the explanation behind them) are absolutely fascinating. For a look at the details of this study and what they found, check out my latest article over at Playboy.

The concept of “pornography addiction” is one that has generated a lot of debate in the popular media. Although pretty much everyone seems to agree that there are indeed some people out there who are distressed about their porn use, there has been much controversy about whether it is appropriate to apply the “addiction” label in such cases. A new study published in Biological Psychology provides provocative evidence in favor of dropping the addiction label because what’s going on inside the brains of so-called porn “addicts” is nothing like what you would expect from someone who has an addiction.

How much do we really know about human pheromones? Not quite as much as the ever-growing number of bottled pheromone peddlers would have you believe. Indeed, it turns out that the scientific study of pheromones is rather complicated. In this TED talk, Dr. Tristram Wyatt explores what we do and don't know about human pheromones. Although he's convinced that humans do indeed have pheromones, he argues that we need to look at the published research in this area with a certain amount of caution and perhaps rethink our approach to studying pheromones in the future. Dr. Wyatt's analysis of this topic is absolutely fascinating and after watching this video, you'll walk away with a greater appreciation for the diverse set of roles that pheromones can play (hint: they go well beyond attraction and mating), not to mention the vast implications that pheromone research might ultimately have for human life.

Kissing is frequently claimed to be a universal or nearly universal romantic behavior. For instance, many sexuality textbooks argue something to the effect that while kissing is common in the U.S. and other Western countries, “it is also very common in most other societies” [1]. On the surface, such claims might seem reasonable in light of research suggesting that kissing may have evolutionary significance. For instance, some scientists have argued that kissing may be adaptive because it allows for an exchange of healthy bacteria, whereas others have claimed that kissing might play an important role in mate choice. In order to make claims regarding the universality of kissing, though, what we really need is a large cross-cultural study looking at whether kissing actually occurs among different groups of people. Fortunately, such a study has just been published in the American Anthropologist, and the results suggest that kissing isn’t quite the universal behavior that has been previously assumed [2].

During the last few decades, sex toys have undergone a major transformation. Manufacturers have gone from producing toys with extremely utilitarian designs to those that pay a lot of attention to aesthetics in an attempt to provide a more lifelike look and feel. But that’s not the only way sex toys have changed. Sex toy manufacturers have increasingly begun to develop products that cater to persons with all kinds of unusual sexual interests. In this article, we’ll take a look at five of the more, um, interesting sex toys I’ve ever come across.

Kegel exercises have been around for more than a half century. In fact, they were first described by Dr. Arnold Kegel back in the 1940s. Although they were initially developed as a means of helping women who experienced urinary control issues after childbirth, researchers and therapists have discovered that they also offer sexual benefits to both women and men.

BDSM (which stands for bondage, discipline, dominance, submission, sadism, and masochism) is a widely misunderstood set of sexual practices. There are a lot of myths and stereotypes out there about both the people who are into BDSM, as well as what it is that they do sexually. Unfortunately, popular media depictions of BDSM (e.g., Fifty Shades of Grey) have only served to reinforce many of these misconceptions. In light of this, here's what you really need to know about BDSM according to the science.

For much of our history, our bodies have been used to separate us into categories that tell us who we are (e.g., male vs. female). However, the more that science has advanced, the more we have come to realize that the categories we created are not as clear cut as we once thought. In this TED talk ("Is Anatomy Destiny?"), Dr. Alice Dreger walks us through history and science to demonstrate that the line separating man from woman (not to mention the lines separating several other social categories) is actually pretty fuzzy.

Using drugs to enhance one’s libido or sexual performance is nothing new, but there are certainly more options today than ever before. This includes prescription drugs (e.g., Viagra for erectile dysfunction and selective serotonin reuptake inhibitors for premature ejaculation), as well as recreational drugs (e.g., crystal meth for heightening arousal and amyl nitrate/“poppers” for enhancing the experience of anal sex). Surprisingly little research exists regarding the prevalence of “medicated sex,” not to mention who does it and the factors associated with it; however, a new study published in the journal Sexually Transmitted Infections provides some revealing insight.

Sexual fantasy is one of the most, well, "fascinating" topics in human sexuality, which is why I am currently running an online survey of sexual fantasies that is designed to be the largest and most comprehensive investigation in this area to date. This study will help us to better understand what it is that people are fantasizing about, how sexual fantasies vary across different segments of the population, as well as what our fantasies mean and where they come from.

Millennials are often portrayed in the popular media as an extremely liberal bunch when it comes to sex. The impression given is that, among other things, millennials are totally cool with homosexuality, they love their casual sex, and they're shunning the notion of marriage. However, this doesn't quite match up with the data. Believe it or not, millennials' sexual attitudes may be a little more conservative on average than you've been led to think.

Previous research has found that both men and women report a wide range of reasons for having sex. In fact, as many as 237 different reasons have been identified! But how do people’s reasons and motivations for sex differ based on the type of relationship they’re in (i.e., casual vs. committed)? And are there differences in sexual motivations based on sexual orientation? A new study published in the Archives of Sexual Behavior offers a revealing look at how relationship type and sexual orientation are associated with women’s reasons for having sex.

"Is it safe to share sex toys with other people as long as you clean them up well, or do you still need to worry about sexually transmitted diseases?"

Thanks for this great question! Sexual health experts have long encouraged people to clean vibrators and other sex toys thoroughly before and after sharing them; however, until recently, no one had ever studied whether this advice was sound. That is, does cleaning a shared sex toy between uses really make it safe? According to a recent study, it's not as safe as you might think.

In this TEDx talk, psychologist Dr. Meg Barker challenges us to rethink the so-called "rules" of relationships. She argues that clinging to the old rules is indeed problematic, but that we can't just dump them completely and come up with new rules because any set of rules will necessarily be limiting. Instead, she suggests we embrace the idea that, when it comes to relationships, there will always be a lot of uncertainty and no set of rules can tell us everything we need to know. Check out the video below for more and share your thoughts in the Comments section.